Abstract Federal agencies and professional organizations have mounted a large effort to address an increasingly recognized public health problem ? poor perinatal oral health ? which has serious implications for maternal and child health and is largely preventable. Several national organizations have issued statements prioritizing the need to improve oral health and access to oral health care during pregnancy and the National Maternal and Child Health Bureau has released consensus statements and clinical guidelines on perinatal oral health care during pregnancy. The provision of the recommended oral health care during pregnancy has the potential to improve women's oral health through improved prevention and restorative care and to promote children's oral health through caregiver education and timely anticipatory guidance. Through funding from the NIDCR (R21DE019211 Adams, PI; U54 DE019285 Chung, PI), we developed and pilot tested the CenteringPregnancy Oral Health Promotion (?CPOP?) Intervention, an oral health intervention for pregnant women attending CenteringPregnancy (CP), a group prenatal care program. The CPOP intervention consists of 2 educational and skills building modules (maternal and infant) that are integrated into the CP curriculum, and delivered by trained CP facilitators. To evaluate the modules, the women completed dental examinations and questionnaires assessments of OH knowledge, attitudes, and behaviors at pre- and post- intervention periods. Infant and maternal salivary bacterial levels were assessed when the infants were 6 and 12 months of age. Findings from the CPOP pilot studies show significant improvements in maternal and infant clinically-assessed oral health. NIDCR funding (R34DE024574) has supported the development of the final planning and preparation for the U01 CPOP RCT. The purpose of this U01 proposal is to test the efficacy of the CPOP intervention as a full scale Phase III randomized controlled trial among a group of women receiving CP prenatal care at sites across Northern California. If shown to be efficacious, CPOP could be implemented rapidly and broadly nationwide.